Weft straightener



July 6, 1965 H. MORTON ETAL WEFT STRAIGHTENER 3 Sheets-Sheet 1 FiledMarch 2-, 1962 MR Mum IWM m fi m/4 u a July 1965 H. MORTON ETAL3,192,595

WEFT STRAIGHTENER 3 Sheets-Sheet 2 Filed March 2 1962 July 6, 1965 H.MORTON ETAL WEFT STRAIGHTENER 3 Sheets-Sheet 3 Filed March 2 1962 IN VEN TOR-S Hunnmcy flfamw Fen k v/ Le-hwaz 9 M #M United States Patent3,192,595 WEFT STRARGH'EENER Humphrey Morton, Rte. 4, Box 450, Danville,Va., and Frank W. Leitner, 1218 Canterbury Road, Charlotte, N.C.

Filed Mar. 2, 1962, Ser. No. 177,127 3 Claims. (Cl. 26-515) Thisapplication is a continuation-in-part of our copending application,Serial No. 77,568; filed on December 22, 1960; for Weft Straightener andAlignment Detector.

This invention relates to a weft straightening device and specificallyto a device for correcting misaligned weft in a traveling strip of wovenfabric whether it be a skew, a bow, or a combination of skew and bow.

In the art of weft sensing and correcting, there have been manyingenious mechanisms devised which will detect and correct both weft andbow, and some to additionally correct a bow-skew condition. However,these prior art mechanisms respond to irregular conditions which are inno way related to the condition of the weft alignment.

The mechanical correction units to which this invention relates arestraight rollers which can be canted across the direction of cloth orfabric travel to correct skew, and bowed rollers which have a middlesection capable of extending into the planes of the fabric to increaseits path of travel to correct bow. A skew-bow condition is correctableby using a combination of such rollers.

The invention provides a weft straightening framework wherein aplurality of bow rollers and a plurality of skew rollers are mounted forindependent movement with respect to each other. Bow corrections aremade by moving the bow rollers into operative engagement with the fabricand skew corrections are made by operatively employing only the skewrollers for influencing the fabric travel. The assembly is such as theestablish a differential tension across the fabric to remove askewed-bow.

The invention provides a unique structure for establishing suchdifferential tension, when required. The Weft alignment portion of thecorrection assembly interposes in the path of fabric travel alternatetype correcting rollers to establish a sequence of, for example, bowroller to skew roller to bow roller to skew roller. In this way the skewroller operates or pulls against a bow roller and visa versa toestablish the difierential tension for removing a skewed bow.

It is significant to note that the invention permits essentially thesimultaneous application of both types of corrections when necessary incontrast with the. machines known heretofore, which sequentially applythe bow correction and then the skew correction, or the skew correctionand then the bow correction. In the invention, partial skew and partialbow correction is introduced by each skew and bow roller. A closed-looperror detection and weft correction system permits such an approach.

Separate driving means is provided for the bow correcting apparatus,which is responsive to a signal indicative of the fact that the fabricincludes misalignment in the form of how error. Similarly, independentdriving means for the skew correcting apparatus is provided, which isresponsive to skew error signals to correct for skew misalignment. Askewed-bow is corrected by driving both sets of correcting apparatus tobring all skew and bow rollers into operative engagement with the fabricto establish the desired differential tension.

Suitable apparatus for developing the skew and bow errors signals isexplained in detail in the afore-rnentioned co-pending appliction,Serial No. 77,568. For purposes of this application only enough of suchapparatus is described to clarify the operation of the correctingapparatus. Sufiice to say that misalignment sampling signals aredeveloped from thread scanning devices preferably disposed near theouter or selvage edges of the travelling fabric. Each thread scanningdevice samples a pair of longitudinally displaced areas of thefabric-each at a predetermined orientation with respect to the fabricpath-to provide a thread count comparison. From such information errorindicating signals can be developed to control the skew and bow drivingapparatus.

With the foregoing in mind it will be apparent that an object of thisinvention is to provide means which will correct skew, bow and skew-bowmisalignments in the weft of woven material.

The invention has as a further object the provision of apparatus capableof establishing differential tensions across a travelling fabric, asdesired, to remove skewedbow conditions therein.

A still further object of the invention is the provision of improvedweft correcting apparatus through the use of skew and bow correctionrollers deployed in a direct alternating sequence.

Another object of the invention is the provision of apparatus permittingthe simultaneous application of partial bow and skew corrections along asection of a traveling fabric.

Further objectives and advantages of this invention will be apparentfrom the following description and claims wherein the construction,arrangement and cooperation of the several parts of the apparatus areset forth.

In the drawings:

FIG; 1 is a floated perspective view of the control arrangement of theinvention in a preferred form;

FIG. 2 is a perspective view of a preferred weft straightening orcorrection assembly;

FIG. 3 is an end view of the rollers of the correction assembly of FIG.2;

FIG. 4 is diagrammatic showing of fabric conditions; and

FIGS. 511 are diagrammatic showings of the relationship between scannedor sensed elements and various thread irregularities in the travelingstrip of cloth.

Referring now to FIG. 1 there is shown an elongated strip of wovenfabric 16 traveling between processing stations. The fabric is drawnthrough a mechanical weft straightening assembly 18 (best shown in FIGS.2 and 3) and thence through a weft counting or sensing station generallydesignated by the numeral 20. After departing from the sensing station,the fabric travels to further processing stations as indicated by thearrow 19.

The fabric is'comprised of warp threads 22 running the longitudinallength of the fabric, and weft threads 2 which run laterally thereof.The longitudinal selvage edges of the fabric are designated as 26 and28. As is well understood in the field, it is important that any lack ofperpendicularity occurring between the weft and warp be promptlydetected and corrected.

FIG. 4 diagrammatically shows the most common misalignments the fabricthreads acquire during process ing. From top to bottom, the sectorsrespectively ac centuate a skew condition 30, a bow condition 31, askewbow 32, a thick stripe condition 33, caused by contaminants, and athick stripe condition 34 caused'by irregular warp densities. Theconditions 30, 31 and'32 are the conditions correctible by the typemechanical assembly to which this invention pertains. Althoughconditions 33 and 34 are not correctible by roller assemblies, they arecapable of transmitting false signals to the sensing devices of theprior art.

Referring to FIG. 1, counting'station 20 is equipped with four identicaloptical systems 36, 38, 4t and 42 for 3 providing bands of lightnecessary for the sensing or counting mechanism. For purposes of thisdescription it will sufiice to say that the systems respectively furnishintensified thin bands of light 37, 39, 41 and 43 for counting purposes.

Spaced below and on both sides of the fabric at station 2t), are fabricsupport tables 44 and 46. The table i has two angularly disposed windows45 and 45 therein near selvage 28, and table 46 has a like pair ofangularly disposed windows 47 and 47' near selvage 26. The pairs ofwindows are so disposed laterally across the cloth that a linebisectingthe angles formed by each pair of windows is a line perependicular tothe path of fabric travel.

The intensified thin bands of light 37, 39, 41' and 43 are directedrespectively at the elongated windows 47, 47', 45 and 45'. Interposedbetween the tables 44 and 46 and their associated light sources are apair of scanning discs 50 and 52. The discs are geared to rotate abouttheir respective axes 54 and 56 at the rpm. proportional to cloth speed.

Each disc is provided with a plurality of pairs of slots (not shown)which traverse the windows at exactly the same instant and at equalspeeds, and thus cause synchronous beams of light to traverse thewindows during the same and equal lengths of time. The travelingsynchronous dots of light are modulated by the weft and Warp threads asthey cross the windows. The modulated dots are indicated by the numerals62, 64, 66 and 68. The actual scanning dots traverse the material atapproximately 30 lagging and leading angles to a line drawnperpendicular to the line of material travel.

Photoelectric devices 70, 72, 74 and 76 pick up the modulated lightbeams and along with counters (not shown) determine the frequency withwhich the threads pass the windows. It is this intelligence which isprocessed to determine weft misalignment and compute the correctionnecessary.

Referring now to FIGS. 5-11, there is diagrammatically shown thealignment of the fabric threads as they pass over the windows duringvarious conditions. The fabric in each illustration is traveling towardthe top of the sheet of drawings. The thread count in windows 45', 45,47' and 47 will arbitrarily be referred to as A, B, C and D,respectively.

In FIG. 5, the warp and weft threads are uniform and perpendicular toveach other. The thread counts A, B, C and D as the fabric passestherepast are equal and no correction signal is necessary or desired.

FIG. 7 demonstrates a forward bow (bow-lead) which results in threadcount A being greater than B, and C being greater than D. Since there isa count difference.

a bow correction signal is sent to the mechanical assembly. It should bepointed out, that the difference in count between the windows of each.pair (e.g., the difference between A and B, or the difference between Cand D) gives the correction indication, and not the count differencebetween the sum of the counts between the pairs of windows.

FIG. 6 indicates a bow-lag which makes count B greater than A, and Dgreater than C. As in FIG. 7, an error or correction signal is sent tothe mechanical assembly and this signal is opposite in sign to that ofFIG. 7.

FIG. 9 shows a skew condition in which the right side is leading. Thisrenders count A greater than B and count C less than count D. Thiscondition transmits a skew correction signal to the mechanicalcorrecting assembly.

FIG. 8 demonstrates a left side leading condition which results in countB being greater than A, and count C being greater than D. This wouldsend an error signal to the correction assembly, opposite to thatdiscussed for the FIG. 9 condition.

FIG. 10 show a thick stripe with a skew condition.

FIG. 11 shows a thick stripe condition where the weft is correctlyaligned with the warp. Here count A equals count B, counts C and D wouldbe partially obliteratedbut would drop off substantially uniformly. Aslong as both pairs remain above an intelligible level, the controlsystem remains balanced and no correction signal is sent. Conventionaldetection devices, comparing counts on either side of the cloth, sendstrong correction signals in response to such a condition.

Compare now on the other hand, FIG. 10 where there is a thick stripecondition and skew at the same instance. Count B is greater than countA, and count C is greater than count D (at least for the short period oftime for which it is exposed). This condition calls for a skewcorrection to be sent to the mechanical assembly. It is true that if acount difference between C and D cannot be determined for long periodsof time, by virtue of a fail safe circuit, no correction is sent inresponse to the AB count. However, starch-caused thick stripes areerratic and as a practical matter a count difference in C and B can bedetermined under all but the most unusual conditions. This unusualcondition is detected when one or more signals drop below the criticaloperating signal which under current operating conditions isapproximately 400 cycles per second.

As the threads both warp (some interference modulation) and weft(primarily), modulate the traveling dots of light, an electricalrepresentation is detected by the photoelectric eyes and transferred tosystems (not shown) of well known type which include counters,amplifiers, frequency detectors and a logic network. Correction signalsare developed for application to the reversible electric skew motor 97-and the reversible electric bow motor 93'.

Referring now to FIGS. 1, 2 and 3, the mechanical correction assembly 13will be described in greater detail. The assembly is supported by asuitable frame including the two parallel side frames, 191 and 193. Apair of bow rollers lit-l and 1% have their ends journaled in said sideframes and are spaced with respect to each other. The rollers havestraight journals 104 and 106, respectively, which extend through theside frame 101 and are held by the arms 108 and 138- of yoke 111. Theyoke 111 is connected by a threaded shaft 112 for movement. The rollerslit-4 and 1% are free-wheeling and as is well known in the art, it isthe position of their curved axles with respect to cloth travel whichgives a bow correction. The shaft 112 operatively connected to motor 98'by way of gear box 113 transfers the desired movement to shaft 112 forpivoting of the bow rollers.

The bow correction is introduced through partial rotation of the bowrollers 10 and through the mechanism described. For example, motor 98responds to the bow correction signal to drive screw shaft 112, therebyimparting a partial rotation to the rollers 1G4 and we. The arms 19:;and 116 are keyed to the journal 1% and lib-5', in turn iournaled in theend plate 1&1. Hence, any vertical movement of the yoke 111 impartsrotary movement to the journals 104 and 1%. Either the flexibility ofthe long shaft 112 or the inclusion of a universal in the gear box 1113enables the slight lateral displacement of the shaft 11?; as it impartsrotation to the bow rollers. The yoke 1111 actually follows a slightlyarcuate path determined by the fixed points where journals i594 and 196'are journaled in the end plate 191. The arms 13S and 11% are pinned tothe yoke 111 to permit slight relative movement, of a pivotal nature, asthe yoke is moved vertically along the arcuate path,

An upright 1&5 is pivotally mounted midway between side frames I01 and3. 33 on cross support bars 117 and 119. A stabilizing arm 167 extendsperpendicularly to the upright and supports bell cranks Mill and 132 ateither end thereof.

Between the side frames and at each end of the bell cranks are twofreely rotating skew rollers 116 and 11S.

which are journaled thereto. The skew rollers are vertically spaced fromeach other and laterally spaced from the bow rollers.

The skew roller brackets 100 and EH92 pivot laterally about the upright105. The pivoting movement is controlled by the motor 97, the bell crank16% being operatively connected to the skew motor via a linkage systemcomprised of worm box 109 and shaft 169.

As shown best in FIG. 3, the path of travel of cloth 16, is as follows:over entrance roller 12%, bow roller H24, skew roller 116, bow roller1%, skew roller 118, measuring roller 122 and exit roller 128. It can beseen that the bow roller axes can pivot into the path of the clothwithout a skew pivot and a skew-bow correction can be accomplished bypivoting brackets and 102 at the same time the bow rollers are in theiroperable position.

The unique sequencing of the rollers gives a much improved correction,and the dual bow and skew rollers act as a dual correction from a singlebow and a single skew error signal. For correction of skewed bow,differential tension across the fabric may be established betivelyconnected to the skew motor via a linkage system tween rollers 104 and116, 116 and 166, and also 106 to 113, for each of these couples work orpull against each other when in operative relation.

The general operation of the entire apparatus is as follows. The fabric16 is received by the structure of this invention from a processingcenter to the right or above in FIG. 3. The fabric travels through thecorrection assembly 18 and passes the weft sensing station 20 anddeparts from the sensing center to further processing centers. Theoptical devices 36, 38, 40 and 42 send a beam of light which ismodulated by the traveling fabric and the modulated signal is picked upby the photoelectric scanning devices 7%), 72, 74 and 76. Theintelligence gained by the scanning heads is sent to the logic network(not shown) which transmits signals back to the motors 97 and 98 of themechanical correction assembly 18.

Therefore, while we have, in the above description, disclosed what wedeem to be the most practical and efiicient embodiment of our invention,it should be well understood that the do not wish to be limited thereto,as there might be changes made in the arrangement, disposition and formof the parts without departing from the principle of the presentinvention as comprehended within the scope of the accompanying claims.

We claim:

1. A Weft straightener comprising in combination means for guidingfabric along a predetermiend path, a series of skew and bow correctingmeans deployed in alternating sequence along the path, said sequencebeing at least skew, bow, skew, bow, means for moving the bow correctingmeans relative to the path to vary the path length of the farbic travelfor correcting bow error, means for moving the skew correcting meansrelative to the path to vary the path length of the fabric travel forcorrecting skew error, and means for endering both the bow and skewcorrecting means simultaneously operative to vary the path forcorrecting a bowed-skew.

'2. A weft straightener mechanism comprising in com bination framemeans; a plurality of rollers supported for rotation by the frame meansto form a path for fabric to be straightened; said rollers including aseries of skew type correcting rollers and a series of bow typecorrecting rollers deployed respectively in alternating sequenec alongthe path for the fabric with adjacent rollers being of diiferent types;means to cant said skew correcting rollers simultaneously relative tothe fabric path to correct weft skew; and means for imparting partialrotation to the bow correcting rollers simultaneously to correct wefthow by altering the length of the fabric path through the mechanism,both said skew correcting rollers and said bow correcting rollers beingsimultaneously operative to vary the fabric path to correct bowed-skew.

3. A weft straightener mechanism comprising in combination frame means;a plurality of rollers supported for rotation by the frame means to forma path for fabric to be straightened; said rollers including a series oftype skew correcting rollers and a series of bow type correcting rollersdeployed respectively in alternating sequence along the path for thefabric with adjacent rollers being of different types; said frame meansincluding means supporting collectively the skew correcting rollers forlateral movement relative to the fabric for introducing skew correctionthereto; skew correcting drive means responsive to a skew correctionsignal to cant said rollers via the supporting means simultaneouslyrelative to the fabric path; said bow rollers being arcuate; means forimparting rotation to the bow correcting rollers to correct for Weft bowby altering the length of the fabric path through the mechanism; and bowcorrecting driving means responsive to a bow correcting signal to impartmovement to said last-mentioned means in accordance with said signal,both said skew correcting rollers and said how correcting rollers beingsimultaneously operative to vary the fabric path to correct bowed-skew.

References Cited by the Examiner UNITED STATES PATENTS 1,384,213 7/21Rowley 26-51 2,623,262 12/52 Berry 2651.5 2,638,656 5/53 Tuttle et al.26-515 2,968,856 1/61 Allen 26-515 2,972,794 2/61 Saul et al. 2651.5

FOREIGN PATENTS 579,505 8/24 France.

761,830 11/56 Great Britain.

DONALD W. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner.

1. A WEFT STRAIGHTENER COMPRISING IN COMBINATION MEANS FOR GUIDINGFABRIC ALONG A PREDETERMINED PATH, A SERIES OF SKEW AND BOW CORRECTINGMEANS DEPLOYED IN ALTERNATING SEQUENCE ALONG THE PATH, SAID SEQUENCEBEING AT LEAST SKEW, BOW, SKEW, BOW, MEANS FOR MOVING THE BOW CORRECTINGMEANS RELATIVE TO THE PATH TO VARY THE PATH LENGTH OF THE FABRIC TRAVELFOR CORRECTING BOW ERROR, MEANS FOR MOVING THE SKEW CORRECTING BOWERROR, MEANS FOR MOVTHE PATH LENGTH OF THE FABRIC TRAVEL FOR CORRECTINGSKEW ERROR, AND MEANS FOR ENDERING BOTH THE BOW AND SKEW CORRECTINGMEANS SIMULTANEOUSLY OPERATIVE TO VARY THE PATH FOR CORRECTING ABOWED-SKEW.